Bacteriophage destroy bacteria but are harmless to humans. They are strain and, usually, species specific, and they are abundant in nature, in foods, and in the intestinal tract of animals. Bacteriophage are about 100 times smaller than bacteria, and they leave no ecological footprint. Bacteriophage are generally recognized as safe (GRAS).
The lytic lifecycle of bacteriophage typically includes adsorption to a bacterial cell, infection, which includes injecting their nucleic acid into the bacterial cell, replication, maturation, and assembly of bacteriophage inside the bacterial cell. The lytic lifecycle culminates in lysis of the bacterial cell to release the progeny bacteriophage.